Conservation biology of the diamondback terrapin in North America: Policy status, nest predation, and managing island populations.

摘要

Reptiles are experiencing global declines and pond turtles (Emydidae) are particularly vulnerable. The diamondback terrapin uses multiple habitats to fulfill its life history requirements, in the estuarine environments of the Gulf Coast and Atlantic states (US). Interacting effects of coastal development, overharvesting, abandoned crabbing gear, road mortality, climate change, and nest predation are likely causing population declines throughout its distribution. Protection levels were assessed by referencing each state's Wildlife Action Plan for the species' Conservation Status Ranking Code. At least 7 federal laws directly or indirectly regulate take, wetland, and/or coastal activities (Lacey Act, CWA, FWCA, NAWCA, WPFPA, CBRA, NEPA). I propose the use of a new term (policy hub species) to describe species that could be used to bring together currently unused laws and protect an entire ecosystem. The majority of terrapin studies have focused on nesting success, road mortality, or incidental take in crab pots or other fishing gear. Patches of upland habitat could facilitate cover for common terrapin nest predators on Virginia barrier islands and high rates of depredation on nests would be encountered near the edges of these patches or other habitat features utilized by these predators. GIS analysis was used to determine if there were any relationships between a depredated nest's location and habitat variables that could increase the likelihood of predation. As a case study of terrapin management in an island marsh system, I summarized three years of field research on the diamondback terrapin population of Fisherman Island National Wildlife Refuge.